Piston skirt expander



Mayll, 1943 c. A. MARIEN ETAL PISTON SKIRT EXPANDER 2 Sheets-Sheet 1 Filed Nov. 19, 1941 May 11, 1943. c. A. MARIEN ETAL 2,319,006

PISTON SKIRT EXPANDER Filed Nov. 19, 1941 2 Sheets-Sheet 2 Patented May 11, 1943 VLJNlTED STATES ISTON SKIRT EXPANDER Charles A. Marien and Melvin W. Marien, St. Louis, Mo., assignorsto Ramsey Accessories Manufacturing Corporation, St. Louis, Mo., a corporation of Missouri Application November 19, 1941, Serial No. 419,705

6 Claims.

Our invention has relation to improvements in expansion and tensioning devices for pistons, which devices are commonly called piston skirt expanders, and it consists of the novel features of construction more fully set forth in the specication and pointed out in the claims.

The present invention is an improvement over that shown in Patent No. 2,198,829 granted to Charles A. Marien on April 30, 1940. It has the same objects as those embodied in said patent, namely, the expanding and reshaping of a deformed piston skirt, and exerting pressure on the inside of said skirt at right angles to the piston bosses; but in addition thereto it is so constructed that it may be more easily handled while being inserted into the skirt or removed therefrom.

The invention, like that of our co-pending application, Serial No. 419,704, also has for one of its objects the embodying in the expander, of ,g

means whereby the supporting members for the expander" are rigidly held against movement throughout the rapid reciprocating action of the piston while in use. A further object of the present improvement is to provide means for augmenting the tension of the expander if desired, which maybe done by inserting either a wedge or an auxiliary spring between the ends of the spring member disposed within the piston skirt. These features as well as others inherent in the invention, will be better apparent from a detailed description of the same in connection with the accompanying drawings, in which:

Figure 1 is a combination side elevation and middle vertical section taken through a conventional-type of piston, showing our improved skirt expander carried by the piston pin, and exerting its tension on the lower part of the piston skirt; Fig, 2 is a bottom plan of the piston showing the skirt expander secured therein; Fig. 3 is a vertical longitudinal section taken through the Ypiston skirt on a plane yindicated by the line 3-3 of Fig. 1; Fig. 4 is a top plan view of my improved expander, showing both the expanded position when not inserted in the piston skirt and the operative position when conned within the piston skirt, and exerting its pressure thereagainst (the latter position being dotted); Fig. 5 is an elevational view of the wedge for insertion between the ends of the' spring member; Fig. 6 is an edge View thereof; Fig. 7 is a top plan of a modified form of expander, wherein an auxiliary spring is inserted between the expander extremities instead of the wedge illustrated in Fig. 5; Fig. 8 is a side elevation of the expander shown in Fig.

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'7; Fig, 9 is a detached view of the auxiliary 65 spring, which is inserted between the ends of the spring member for augmenting the tension thereof; Fig. 10 isa plan View of a further modiiication of our invention; Fig. 11 is a side elevation thereof; and Fig. l2 is a cross-sectional detail taken on the line I2-I2 of Fig. 11.

Referring to the drawings, P represents a piston of a typical construction having the usual pin bosses I, I, for supporting a piston pin 2, which holds the connecting rod 3 and the piston P in operative relation.

As stated above, after the piston P has been in use for some time, the skirt portion thereof wears and often becomes distorted, so that it no longer fits properly in the engine cylinder. When this condition becomes severe, the piston must either be replaced or restored to its proper shape. In the majority of instances the wear is not sufciently severe to require replacement of the piston, but the latter may be re-shaped and provided with a skirt expander as illustrated in Figs. 1 to 4, inclusive. In the present improvement the skirt expanderv embodies an annular spring member 4 (preferably in the shape of an elongated oval), having parallel sides 5, 5', 5', and arcuate end portions E, 6, which constitute the expanding parts of the expander. The side portions`5, 5', are separated by a gap y, and have their ends bent outwardly at right angles to provide fingers 'I, 'I, which may be gripped by an appropriate tool for the purpose of contracting the spring member 4 as "a whole, whereby it may readily be inserted or removed from the skirt S of the piston. The ends I', 1', of :fingers 7, I, are bent inwardly so as to provide a channel in the gap y, to receive a wedge 8, which is in'- serted in said gap after the expander is positioned within the piston skirt S, and wedged therein between the ngers 1, l, extremities 1', 1', thereof, and sheet metal supporting ear 9'. There are a pair of supporting ears 9, 9', which have perforated lobes I0, I0', at their upper ends and extended channel-shaped formations II, II', at their lower ends. The channels I I, II', are provided with upwardly turned retaining portions I2; I2', whereby the sides 5, 5', 5', of the spring member 4 are securely held in assembly'relation withthe supporting ears 9, 9. The outwardly presented wall I3' of channel II', is provided with an opening iii, through which the fingers l, l, of spring member 4 project (Figs. 1 and 4).

As may be seen in Fig. 2, the ears 9, 9', are coniined between bosses I, I, and connecting rod 3, and the channel members II, II', are

of a length that they fit snugly between opposite portions of piston skirt S, so that when the skirt expander is mounted within the piston skirt it is securely held in place, so that there is no possibility of its working loose under the forces to which it is subjected when the piston is in operation. As a matter of fact, if the spring member 4 should break because of the severe action to which it is subjected and thus become detached from the supporting ears 9, 9', the latter will still be unable to work loose, as theB7 are confined in one direction between bosses and connecting rod 3, and they are confined in a direction at right angles thereto by contact of the piston skirt with the ends of channel members Il, Il'. If it were not for the Contact of the channel members Il, with opposite portions of the piston skirt, the supporting ears 9, 9 would be free to oscillate upon detachment from the spring member 4, and impinge against the inner surface of the piston skirt, causing damage thereto.

When the spring member 4 is in its relaxed condition (that is, not under tension within the piston skirt) its length from one end to the other is greater than the inside diameter of the piston skirt, so that after being contracted and inserted within the skirt, it exerts considerable force outwardly on said skirt in the direction at right angles to the pin bosses. This of course imparts a somewhat cam-shape to the piston skirt, and approximates its original shape before having become distorted through use.

Referring now to Figs. 7 to 9, inclusive, 20 represents a slightly modified spring member in that fingers 2|, 2|, thereof, at the ends of the spring member 20, are slightly longer than in the form illustrated in Figs. l to 4, inclusive, and have inserted between them an auxiliary spring 22, the ends 23, 23, of which are turned outwardly to bear against the ends of fingers 2|, 2|.

Obviously the auxiliary spring 22 is inserted after the expander is in position in the piston skirt, and of course passes through opening |4 of wall I3 of the channel Fig. 9 shows a detached view of spring member 22 with the sides 22', 22', thereof diverging outwardly, so that when said sides are forced together for positioning between the fingers 2|, 2|, they will exert considerable tension upon the ends of the spring member 22, and augment the tension thereof.

From the foregoing it is apparent that the extended portions Il', of the supporting ears 9, 9', not only securely hold the spring member 4 within the piston skirt S, but are themselves confined within said skirt in such a manner that under no conditions can they work loose. Our improved expander also has the advantage over Vsimilar type of expanders as heretofore made, in that the placing of the gap g in the side of the spring member 4 instead of in the end, permits of greater contraction of the spring element, and of course consequently greater tension upon the piston skirt when inserted therein.

In the modified form of the invention shown in Figs. 10 to 12 inclusive, spring member 25 of the expander has bights 26 formed at each Corner between the ends 21, 21, and sides 28, 2S', 28. The purpose of the bights is to introduce additional fiexibility to the spring member 25 as a whole, and permit the spring member to yield inwardly at the corners when wedge 29 is forced in place in the gap g' between the extremities 30, 3U, of the spring member.

Obviously other modifications of our invention will readily suggest themselves to the skilled mechanic, and we do not wish to be restricted to the precise details of construction herein shown.

Having described our invention, we claim:

l. A piston skirt expander comprising an expanding element having side members and piston skirt engaging members, a supporting element secured to each of said side members, each of said supporting elements having laterally extending abutments, and an auxiliary spring in cooperative relation with the expanding element to augment the tension thereof.

2. A piston skirt expander comprising a spring element of the general shape of an elongated oval having a gap in one side thereof and outwardly projecting fingers adjacent to said gap, a supporting element secured to each side of said spring element, and a Wedge disposed in the gap between said projecting fingers.

3. A piston skirt expander comprising a spring element of the general shape of an elongated oval having a gap in one side thereof and outwardly projecting fingers adjacent to said gap, and an auxiliary expanding element disposed between the projecting fingers and in cooperative relation therewith.

4. A piston skirt expander comprising a spring element of the general shape of an elongated oval having a gap in one side thereof and outwardly projecting fingers adjacent to said gap, a supporting element secured to each side of said element, extended abutment portions on the supporting elements, and auxiliary expanding means disposed between the projecting fingers of the spring element.

5. In combination with a piston having a skirt and piston pin bosses for the reception of a piston pin, a piston skirt expander comprising a spring element having side members and skirt engaging members, a supporting element secured to each of said side members, each supporting element having a perforated lobe for receiving the piston pin and an extended portion for engagement with the inside of the piston skirt expander, and auxiliary expanding means in cooperative relation with the spring element.

6. A piston skirt expander comprising a spring element of the general shape of an elongated oval having a gap in one side thereof and outwardly projecting fingers adjacent to said gap, an auxiliary expanding element disposed between the projecting fingers and in cooperative relation therewith, and bights formed in said spring element to permit yielding thereof under tension imposed by the auxiliary expanding element.

CHARLES A. MARv IEN. MELVIN W. MARIEN. 

